Since the update, there is now a huge margin between the two columns, and on the right side. I must now reduce the text size to an unreadable size, in order to get the two columns to show. How can I reduce the margin on the right hand side, and the margin between the columns?

You can adjust the values under Settings->Text File Settings->Page Margins. Are you experiencing this issue with text files or chord pro files? I definitely did not see that issue when testing with chord pro files.